It was mentioned here a few months ago. I have it installed and it works okay where the user has left their account and photos on Photobucket - i.e. where, without the extension, you get an image saying "upgrade your account".
But a lot of users - including I think DaveW - deleted their Photobucket accounts completely. If you see an "image not found" message then no browser extension will display the picture.
~iw
